NEW YORK (AFP) - The S&P 500 and Nasdaq finished at fresh record highs on Friday (Sept 29) as Wall Street closed the books on a solid third quarter amid renewed hopes that Washington will cut taxes.

The S&P 500 gained 0.4 per cent to 2,519.36, its second straight record, while the tech-rich Nasdaq jumped 0.7 per cent to 6,495.96.

The Dow Jones Industrial Average gained 0.1 per cent to 22,405.09.

Analysts said investor sentiment remained upbeat after all three indices advanced in September, historically one of the worst months of the year for stocks.

"We've actually had quite a good performance," said David Levy, portfolio manager at Republic Wealth Advisers. "Overall, the market is looking ahead to what could be a positive fourth quarter."

Money managers have been cheered by the release of President Donald Trump's tax cut plan, as well as expectations of solid earnings.

Analysts estimate companies in the S&P 500 will report a 4.2 per cent rise in profits in the third quarter compared with a year ago, according to Factset. Earnings season gets started in earnest in about two weeks.

"The buzz about a tax cut Bill and the possibility of a solid earnings season on the way has investors putting sidelined capital to work," said a note from Gorilla Traders strategist Ken Berman.

Tech shares were generally strong, with Facebook winning 1.3 per cent, eBay 1.9 per cent and Google parent Alphabet 1 per cent.

Tyson Foods jumped 7.6 per cent after lifting its full-year profit forecast by 25 cents to US$5.20 to US$5.30 per share due to better than expected earnings in its beef business. The meat company plans to cut 450 jobs.

Homebuilder KB Homes surged 8.6 per cent after reporting that third-quarter earnings rose 27.6 per cent to US$50.2 million.